The present invention relates to a filter circuit in a hydraulic lubrication system.
Agricultural tractors have hydraulic systems which include hydraulic pumps which supply pressurized hydraulic fluid to various hydraulically operated devices such as a steering system, a hitch system, selective control valves (SCVs) connected to hydraulic cylinders, and a transmission which includes hydraulically operated control valves and a hydraulic lubrication circuit. The SCVs have been located at different locations on the tractor, including middle and rear locations. For example, rear SCVs are connected by hydraulic couplers to hydraulic cylinders on an implement coupled to the tractor. The hydraulic pumps draw or suck hydraulic fluid from a sump or reservoir which may be formed by a housing such as a gear box housing.
Contaminants can be introduced into a hydraulic system at the implement hydraulic components, the couplers, and at other points.